The present invention relates to plumbing installations, and more particularly, to a new design for the mechanisms contained within the water tank of a household toilet which improve the flushing efficiency thereof.
For many decades, conventional household toilets have used a generally rectangular porcelain tank mounted immediately above a porcelain bowl from which five to seven gallons of water are rapidly drained in order to flush the waste into the sewer system. One very common design uses a flapper valve made of an elastomeric material that normally covers the drain outlet of the tank. When the flush handle on the outside of the tank is manually depressed the flapper valve is lifted and the head of water in the tank drains through the drain outlet into the bowl. The flapper valve is designed so that it initially floats as it is lifted away from the drain outlet in the bottom of the tank. This allows sufficient flushing water to flow into the bowl even if the user immediately releases the flush handle. There is typically a ballcock valve mounted on the left side of the tank which is connected to a pressurized water line in the house. When the tank drains, a float ball connected to the ballcock valve descends. This turns the ballcock valve ON and it begins to refill the tank with water at a rate much slower than the rate at which water flows through the drain outlet. When the tank is nearly empty, the flapper valve closes. The tank continues to refill as the float ball connected to the ballcock rises. At the same time water from the ballcock valve enters an overflow tube and refills the bowl to the normal standing water level. This provides a trap seal. Once the float ball reaches a predetermined height indicating that the tank is full, the ballcock valve completely turns OFF.
The foregoing conventional household toilet is wasteful and inefficient since a relatively large quantity of water is used to accomplish each flush. This is because the limited elevation of the tank provides only a modest water pressure head. The pressure head is obtained from the potential energy stored in the tank. As the body of water flows through the drain outlet of the tank, it starts the siphoning action and flushes the standing water in the bowl and its waste contents into the sewer line.
Simply increasing the volume of the tank but leaving it directly mounted adjacent the top edge of the bowl in order to achieve a greater pressure head wastes even more water. Another approach which is used in Europe is to mount the tank on the wall near the ceiling and to connect the drain outlet of the tank to the bowl with a pipe as a way of increasing the pressure head. This European approach is generally considered too unattractive and unsafe for use in the United States. Toilets have also been commercialized with pressurized tanks to improve flushing efficiency. However, these toilets have been too costly to manufacture and assemble and they lack the reliability needed for thousands of flushes.
Fresh water is becoming an increasingly valuable natural resource. Many geographic regions of the United States, such as Southern California, have experienced prolonged periods of drought. Arid parts of the country often take water from remote locations whose environments suffer as a result. For example, Los Angeles diverts large amounts of water from Mono Lake which has shrunk significantly since the 1930's. Furthermore, the more water that is flushed down toilets, the more volume of sewage there is that must be treated. Sewage delivery systems and treatment plants are expensive to construct and maintain. Treatment plants require large amounts of land and have offensive odors. Residents near any proposed sewage treatment site will often object vehemently.
According to a Dec. 19, 1980 report by the U.S. Environmental Protection Agency (EPA), approximately 40% of the water used in a home is flushed down the toilet. The typical toilet in the U.S. uses between 3.5 and 7 gallons of water per flush. Effective Jan. 1, 1994 a new Federal law will require the installation of toilets in all new construction that use 1.6 gallons or less of water per flush. There is a critical need to ensure effective flushing in such toilets for sanitation reasons. Also, unless the flushing action in such low water volume toilets can be made efficient, users will flush them twice during each visit to the bathroom to ensure a complete flush, thereby negating the intended water savings.
There is also a critical need to design an apparatus to retrofit existing 3.5, 5 and 7 gallon toilets to lessen the amount of water used during each flush while maintaining an effective flush. Various approaches have been heretofore employed in regions subject to water rationing to reduce water consumption by conventional toilets. These have included lowering the tank level or introducing a brick or dam to decrease the water volume released during each flush. However these approaches have generally been unsatisfactory because the consequent reduction in water flow into the bowl often results in incomplete flushing. Users then flush twice, compounding the waste of water.